Rotary engine.



No. 784,614. PATBNTED MAR. 14, 1905.

' J. D. BUCHANAN.

ROTARY ENGINE.

APPLICATION FILED JULY 29,1904.

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v PATENTED MAR. 14, 1905. J. D.BUGHANAN.

ROTARY ENGINE.

- APPLIOATION FILED JULY 29,1904.

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- Witnesses Inventor.

Attorneys Patented March 14, 1905.

PATENT OFFICE.

JOHN D. BUCHANAN, OF MEMPHIS, TENNESSEE.

ROTARY ENGINE.

SPECIFICATION forming part of Letters Patent No. 784,614, dated March14, 1905.

Application filed July 29, 1904. Serial No. 218,716.

- **Tennessee, have invented a new and useful Rotary Engine, of whichthe following is a specification.

This invention relates to rotary steam-engines, andhas for its principalobject to provide a perfectly-balanced easy-running engine for use inplaces where the pressure of steam is in excess of that actuallyrequired for the operation of the engine.

In river-boats carrying freight from landing to landing and especiallyin larger boats where the boilers frequently carry from two hundred totwo hundred and fifty pounds of steam-pressure for the operation of thepropelling-engine it is necessary when landing to either draw the firesor to allow the steam to escape from the boiler in order to preventdangerous increase in pressure during the time the engines areinoperative. The lat ter course is universally followed and the steam isallowed to escape to the air or water and is wasted. In modern practicethe load- 'ing and unloading of vessels is in many cases accomplished bymeans of small engines which operate conveying devices, and theseengines, which Work best at a pressure of less than one hundred pounds,cannot consume all of the high pressure of the boilers, so that evenduring the operation of unloading at landings there is still anunavoidable waste of steam. It is found, moreover, that in the use ofthese loading and unloading engines, especially of the rotary type,excessive wear occurs when high-pressure steam is admitted to saidengines, and the movable piston-wings are thrown in and out so rapidlyand with such force that the engine is soon unfit for use.

The present invention therefore is designed to overcome difficultiesformed in the operation of small rotary engines where the steam-pressureis in excess of that required for the operation of the engine and toutilize the excess pressure in balancing the engine, so that all of themovable parts may practically ride on the steam and injury to the partsprevented. All of the steam-pressure will thus be utilized to someadvantage, although all of the pressure and force of the steam is notconverted into power, and it is to be understood that the present engineis not constructed with a view of economically using steam, but ratherwith a view of utilizing to some advantage steam which otherwise wouldbe wholly wasted.

A further and important object of the invention is to [obtain an almostperfect balance by the introduction of steam simultaneously at both endsof the cylinder and its exhaust at the center of the cylinder, so thatsteam will not be compelled to travel across the cylinder, and thussubject different portions of the piston-wings to varying pressure.

With these and other objects in view, as will more fully hereinafterappear, the invention consists of the novel construction and arrangementof parts hereinafter fully described, illustrated in the accompanyingdrawings, and particularly pointed out in the appended claims, it beingunderstood that various changes in the form, proportions, size, andminor details of the structure may be made without departing from thespiritor sacrificing any of the advantages of the invention.

In the accompanying drawings, Figure 1 Similar numerals of reference areemployed for the reception of a transversely-disposed shaft 5, to'whichis secured the cylindrical piston-drum 6. The piston-drum is providedwth two sets of wing-receiving recesses Sand 9, the recesses overlappingand being disposed in staggered relation-that is to say, the recesses 8extend from one end of the cylinder to a point somewhat beyond thecenter and the recesses 9 extend from the opposite end of the pistonalso to a point beyond the center, so that the recesses will to someextent overlapand each recess of one set is disposed midway between twoadjacent recesses of the opposite set. In the several recesses arearranged piston-wings 10, that move in lines radial of the piston-druminto contact with the inner surface of the cylinder, being proj ectedoutward into the steamspace under steam-pressure and being forced inwardas they gradually ride against the two abutments 11 and 12, that areformed integral with the cylinder, and in this connection it is to benoted that the two steamspaces are arranged in vertical alinement withone above and one below the pistondrum, so that the pressures beingequal at the top and bottom the bearings will have to support no morethan the weight of the pis tondrums and there will be no auxiliarypressure or impact of steam imposed upon them.

Each of the cylinder-heads 2 and 3 is provided with a pair ofsteam-inlet ports 12, the two ports of each head being in communicationand being supplied with steam through a main steam-pipe 14, and thesesteam-inlet ports are arranged at points immediately in advance of theabutments at both cylinderheads, so that steam will simultaneously-enterfrom both ends of the cylinder, and endwise pressures on the piston willthus be balanced, the steam during the operations of the engine movingtoward the center of the cylinder and escaping through ports 16 formedin the wall of the cylinder. The steam entering from one end of thecylinder will be met by steam under similar pressure entering at theopposite end of the cylinder, and the steam will therefore exercisepractically uniform pressure at all points in the length of thepiston-wings, the end thrust and irregular torque of engines which feedat one end and discharge at the other being thereby overcome.

In each end of the piston-drum is arranged an annular recess 18, incommunication with all of the )iston-wing-receiving recesses, and saidannular recess is further in communication with a port 19, leadingthrough the bearing to said port, being supplied with steampressurethrough a pipe 20 and the steam passing through the annular recess andto all of the piston-wing-receiving recesses, so that piston-wings willbe held outward in contact with the inner curved wall of the cylinder.It is found that when the pressure of steam is in excess of thatrequired or even operating under ordinary pressure the outward movementof the piston-wings will result in considerable noise when the wingsstrike the walls of the cylinder, and, furthermore, there isconsiderable unnecessary wear on the outer edges of the wings and thesurface of the cylinder with which they are in contact. T o overcomethis difficulty, the inner curved wall of the cylinder is provided witha number of grooves 21, which extend completely around the cylinder, andwith these grooves communicate steam-supply pipes 22, which may beconnected directly to the boiler or to the main steam-pipes, the steambeing preferably directed in lines tangential to the piston-drum, sothat the impact of the steam will to some extent be utilized on thewings as they successively move outward into the steam-space.

Each of the piston wings is provided with one or more projecting lugs23, that are of a width slightly greater than the thickness of the wing,presenting a rather extensive surface that is arranged at an obliqueangle to the general lines of the wing. These lugs enter the grooves ofthe cylinder, and their inclined faces are so presented that the currentof steam passing through the grooves must act to force the piston-wingsinward toward the center of rotation of the drum, the inclined face ofeach lug being so arranged with relation to the adjacent wall of thegroove that the steam must flow througha gradually-contracting space, sothat the pressure is utilized to the best advantage in resisting theoutward pressure of the steam which enters the wing-receiving recessesof the piston. The inner and outer faces of the piston-wing are thusboth subjected to pressure, the two forces being opposed to each otherand the piston-wing being thus balanced to some extent, so thatfrictional wear between the outer edge of the piston-wing and theadjacent surface of the cylinder will be minimized. The area of thegrooves and lugs is of course properly proportioned with respect to thearea of the wings, the latter area being of course the greatest, so thatthe steam cannot act to force the wings wholly within the recesses, andthus prevent the operation of the engine.

It is to be understood that this invention is intended for use onlywhere the steam or other fluid under pressure may be wasted, and itwould be of little or no value where economy of operation is essential.

Having thus described the invention,what is claimed is- 1. In a rotaryengine, a cylinder provided with a continuous groove in its innercircular wall, a drum arranged within the cylinder and provided withwing-receiving recesses, and wings mounted within said recesses andprovided with projecting lugs entering said groove.

2. In a rotary engine, a cylinder having a grooved Wall, a piston-drumprovided with wing-receiving recesses, and wings mounted in the recessesand provided with lugs adapted to enter the grooves, said lugs havingtheir faces arranged at an oblique. angle with respect to the bottom ofthe groove.

3. The combination in a rotary engine, of a cylinder having a groovedinner wall, a drum arranged within the cylinder and provided withpiston-wing-receiving recesses, a plurality of wings arranged in therecesses and each having a projecting lug adapted to enter the groove,the Width of the lug being greater than the thickness of the wing.

4. The combination in a rotary engine, of a cylinder having a groovedwall, a piston-drum having wing-receiving recesses, a wing disposed ineach recess and provided with a lug projecting beyond the general lineof the outer edge of the wing, the width of the lug being greater thanthe thickness of the wing, and its outer face being inclined withrespect to the outer edge of the wing.

5. The combination in a rotary engine, of a cylinder having a grooveforming a continuous steam-passage, a drum arranged within the cylinder,and piston-wings carried by the drum and provided with projecting lugsthat partly enter said groove.

6. The combination in a rotary engine, of a cylinder having steam-inletports at its opposite ends and provided with an approximatelycentrally-disposed escape-port, a drum arranged within the cylinder andhaving a pair of sets of wing-receiving recesses arranged in staggeredrelation, and piston-wings disposed in said recesses.

7. The combination in a rotary engine, of a cylinder having steam-inletports at its opposite ends and provided with an approximately centrallydisposed escape-port, apiston-drum Y cylinder having a pair ofinlet-ports disposed at its opposite ends and provided with anapproximately central escape-port, a pistondrum disposed within thecylinder and having a pair of sets of piston-wing-receiving recessesdisposed in staggered relation, and a pair of sets of piston-wingsdisposed in the recesses and having their adjacent ends overlapping. Intestimony that I claim the foregoing as my own I have hereto affixed mysignature in the presence of two witnesses.

JOHN D. BUCHANAN. Vitnesses J. H. JoonUM, Jr., J. M. WALKER.

